Method and apparatus for cleaning liquid



Sept. 26, 1967 P. KOSAR 3,344,052

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. INVENTOR. I PETE? kosAz United States Patent 3,344,662 METHQD ANDAPPARATUS FOR CLEANING LIQUID Peter Kosar, Garden City, Mich, assignorto Ajem Laboratories, Inc., Livonia, Mich. Filed May 14, 1964, Ser. No.367,437 8 Claims. (Cl. 210-23) ABSTRACT OF THE DISCLOSURE Method andapparatus for separating a liquid from a mixture of liquids havingdifferent dielectric properties, by means of a continuous belt having adielectric constant similar to that of the liquid separated.

This invention relates to method and apparatus for separating liquids inindustrial processing baths. More particularly, the invention relates toapparatus for removing liquids of substantially different dielectricproperties by selective adsorption of one of the liquids on a continuousbelt having dielectric properties similar to those of the liquid beingadsorbed thereon.

During industrial machining operations, lubricating oils necessarilycome in contact with the parts being machined. A considerable amount ofthis oil remains on the surface of the machine part and is carried withthe part to subsequent finishing operations. The economic and efficientremoval of this oil from the part has become an industrial problem. Theproblem is manifest in such equipment as washers wherein a machine partis subjected to washing action for the purpose of removing trap metalchips, dirt, etc. by heavy washing action.

The Washing solutions applied to the part in these washers usuallycontains an amount of detergent which is of some use in dispersing oilwhich contaminates the washing solution. However, even with effectivedetergents there may be no more than to of oil emulsified in the washingsolution, based on the total weight of the solution; and even when theserelatively large amounts of oil are emulsified in the washing solution,the effectiveness of the wash is materially reduced because of smalldeposits of oil left on the Washed parts by the oilbearing washingsolution. In many washing operations the quantity of oil increases asthe operation proceeds and sometimes reaches a quantity totalingone-half of the volume of liquid within the equipment.

When this large quantity of oil is present in, for example a washerapparatus, the oil segregates out of the wash solution and floats on thesurface. Because many cooling oils contain volatile hydrocarbons,serious fire hazards may occur and whole areas of industrial plants mustbe subjected to special precautions against the ignition of the volatilehydrocarbons and moreover the fumes may constitute a health hazard.

Another serious problem caused by the accumulation of emulsified oil inthe power washer is that disposal of washing fluids becomes moreburdensome. Increasing municipal and state regulations tend tolimitdrastically the amount of foreign materials that are discharged intostreams, etc. Thus, the presence of large quantities of oil inindustrial liquids such as washing mixtures may require that the entirevolume of liquid be given separate and special treatment before beingdischarged into bodies of water protected by anti-pollution regulations.The removal of the major quantity of the foreign material often rendersthe liquid acceptable for discharge into such protected streams.

Furthermore, it is clear that in some cases, such as the recovery ofthese oils, the recoverer obtains a material dfi itfidz Patented Sept.26, 1967 ICC that can be used in a plant operation, and thereby savesthe cost of new material for that operation.

The usual methods of removing oils from aqueous solutions have a numberof disadvantages to the industrial user. For example, the use of anoverflow pipe or weir to skim off oil is restricted to equipment where aconstant liquid level is maintained. In many types of apparatus theliquid level often drops irregularly because of the nonuniformity ofsupply to the apparatus. Large quantities of oil may build up in suchequipment far below the level of any overflow pipe or weir.

In view of the preceding problems, it is an object of the invention toprovide an economical and efficient method of separating liquids ofdifferent polar characteristics. Another object of the invention is toprovide a continuous belt separator having greatly increased capacityover belt-type separators of the prior art. It is another object of theinvention to provide a belt-type separator useful for separating oilfrom water and also useful in separating metallic chips from liquidmedia. A further object of the invention is to provide a liquidseparator of the belt-type wherein an optimum quantity of liquid to beseparated is picked up on the belt. It is a still further object of theinvention to provide a belt-type liquid separating apparatus whereon theliquid is most easily separated from the belt and disposed of. Applicanthas in the instant invention provided apparatus meeting the foregoingobjects.

Applicants invention comprises an apparatus comprising a continuous belttraveling around pulleys, at least one of the pulleys being submerged inthe liquid mass to be subjected to the separating operation and a methodfor operating said apparatus. Of course, the belt may also be carried ona single pulley above the liquid or partially submerged from which thebelt passes down into the liquid.

Advantageously, the submerged pulley is placed just below the surface ofthe liquid mixture to be treated and is placed in a relatively calm,i.e. non-agitated, area of the liquid. This placement of the submergedpulley has a two-fold purpose. First, low agitation will lessen thetendency for any amount of, for example, oil which adheres to the beltas it enters the liquid, being mechanically removed from the belt duringthe time it is submerged. Secondly, the fact that the pulley issubmerged to only a small depth will minimize the time during whichdensity differential between the liquids being separated may act on thelighter liquid and tend to lift it off of the submerged belt.

In advantageous embodiments of the present invention, the submergedpulley is of irregular shape, i.e. not a smooth drum. Smooth drums tendto force the liquid being separated off of the drum surface of the beltcontacting the drum. The pulley may be polygonal in crosssection, mayhave a face comprised of wire mesh, may be perforated, may have cleats,may comprise spokes, and may comprise a simple coil, or reversed coils.When a pulley with reverse coils is moved at a different speed from thebelt, the reverse coils tend to force any oil on the inside of the belttowards the center of the belt, or the sides of the belt, thus aidingits later removal by scraping or wiping action. 7

Oil adhering to the belt is carried out of the liquid surface andremoved from the belt before the belt is returned to the liquid. Amongthe suitable forms for means of removal are squeegee-type scrapers,squeeze-type rollers, suction action on the belt, and jets of air orother gas pressure to blow the liquid from the belt surface.

Suitably, the material of which the belt is constructed is of polarcharacter similar to that of the liquid which it is desired to pick upon the belt. For example when oil is being removed from an aqueousmaterial, the surface of the belt should be a material which has a lowdielectric constant and is relatively free of polar materials. Inremoving oily materials from water, for example materials withdielectric constants up to about 5, the belt surface may conveniently beof a material having a dielectric constant of up to about 5. Preferablysuch materials as Teflon and polyethylene with dielectric constant ofabout 2 and 2.3 respectively are used. Neoprene and rubber belts mayalso be utilized.

When ferrous-type impurities are dispersed in the liquid from which forexample oil is being removed, it is advantageous to have the core of thebelt comprised of some material having magnetic character. Such a beltnot only tends to pick up the oil but also tends to pick up any magneticimpurities such as ferrous shavings and chips. These impurities may thenbe removed before the belt is returned to the liquid.

The term belt as used herein is intended to define not only continuousbelts of sheet-like configuration but also to define all otherconfigurations of surfaces which may be passed continuously in and outof the liquid mass being subject to separation. For example tubular typebelts having grooves running parallel to the axis of the tube or havinglateral fins on the tube circumference may be used. Belts of suchconfigurations are especially useful in that they provide a largesurface area and take up little space.

The belts may also have perforations of varied shape and size. In manycases such perforations are advantageous in that they allow liquid toflow freely to the inside of the belt, i.e., the side that contacts thepulleys, and thereby allow the inside of the belt to do a substantialpart of the separation.

In some embodiments of the invention it is desirable to have anonuniform belt surface, that is a belt surface which is insufiicientlysmooth to allow the liquid removing means, like a squeegee, to removethe liquid completely. It is usually advantageous to have a small amountof the liquid, which has been preferentially absorbed onto the belt,still coating the surface of the belt on its reentry into the liquidreservoir because such a coated surface has the greatest possiblecompatibility with liquid still to be removed and thus aids theseparation operation.

Thus, pebbled, grooved, ribbed and other surfaces of relatively shallowirregularities are especially advantageous.

In the drawings:

FIGURE 1 is a view in elevation showing an embodiment of the apparatusof the present invention placed within a tank shown in section.

FIGURE 2 is a view in elevation showing the apparatus of FIGURE 1 fromthe side.

FIGURE 3 is an enlarged view of the means for removing liquid from thebelt also seen on FIGURE 2.

FIGURES 4 through 9 are a series of schematic diagrams showing a numberof different arrangements of the apparatus of the present invention.

FIGURES 10 to 13 and 15 show schematic diagrams of several differentmethods of removing liquid from the surface of a continuous belt.

FIGURE 14 shows a schematic section of a magnetictype separator.

FIGURES 16 through 20 show some of the pulleys advantageously used onthe apparatus of the present invention.

Referring to FIGURES l and 2, upper pulley and lower pulley 32 arerotatably mounted on frame 34. The upper pulley is rotated by motor 36through reducer 38. Around these pulleys, a continuous belt 40 rotatesin a counterclockwise direction. This belt, in the preferred example,has its surface coated with a synthetic rubber material sold undertradename Neoprene by E. I. du Pont de Nemours Co., having a dielectricconstant of 4.1. The lower pulley 32 is placed beneath the level ofliquid mix- 4- ture 42 in tank 44. A normal linear speed of the belt is32 f.p.m.

The liquid mixture 42 in the tank 44 comprises two liquids, one alubricating oil of low dielectric constant about 2 to 4, the otherwater. When detergents are present in the liquid, the aqueous phase maycontain, for example, about 1% of oil in an oil-in-water emulsion.

As belt enters the water and passes around lower pulley 32, oilpreferentially coalesces on the belt. Side plates 46 on the pulley 32are perforated, allowing the liquid mixture to circulate freely into theinside of the cylindrical sheave of pulley 32. The curved face 48 ofpulley 32, as shown in FIGURE 16-, is made screen-1ike, allowing oil tobe preferentially picked up on the side of the belt next to the pulley,in addition to that on the outer side of the belt. Oil adhering to thebelt 40 is carried out of the liquid and up around pulley 30.

FIGURES 17 through 20 show other forms of skeleton drums which likewiseprovide access to the under side of the belt. The same purpose isaccomplished by the pulley of FIGURE 20; however, the belt is maintainedat a position away from the surface by cleats 60 allowing liquid tocontact the pulley-side of the continuous belt. The pulley of FIGURE 17is open-faced and has rods 62 connecting side plates 46. Particularlyadvantageous are the pulleys shown in FIGURES l8 and 19 wherein atubular coil is used. Not only do these pulleys allow both sides of thebelt to be exposed to the liquid to be removed, but these pulleys, whenoperating at different linear speeds than the belt speed, also providemeans for pushing the liquid to either side, or the middle, of the beltfor easier removal. This pushing is done by coils 64. The speed isachieved by allowing the pulley to slip against the oily surface of thebelt. Coils 64a of FIGURE 19 are reversed on opposite sides of thecenter for pushing liquid on different areas of the belt in differentdirections, for example, to either side of the belt.

Most of the oil is removed from belt 40 as it is passed between wipers50 mounted angularly across the face of the belt. The removed oil flowsinto troughs 52 and is carried to storage or disposal facilities, notshown. In one actual installation, the rate of oil removal is about 0.75gallon per minute.

An especially advantageous embodiment of the invention is illustrated inFIGURE 14. A magnetic material is compounded into the core of belt 40a,e.g., Alnico or other strongly magnetic material embedded in the rubberbelt. The surface of the belt 40a is given a finish of neoprene. Thisbelt then forms an effective scavenger for iron dust and other magneticmaterials in the liquid mixture being processed. Referring to FIGURE 14,belt 40a is carried around pulley 30a and is brought into closeproximity to a strong electromagnet 61) which attracts the iron dust.The electromagnet causes chips of magnetic metals to be taken fromcontinuous belt 40. Electromagnet 6G is stationary and is mounted withinroller 61 which is manufactured substantially of a nonmagnetic material.From time to time the magnet 60 is deenergized and the iron chips arebrushed off by rotating outer protective drum 58 against scraper 59which is placed beyond the influence of electromagnet 60 and ispositioned to intercept the iron dust as it is carried around the magneton roller 61 which is rotating clockwise as seen in FIGURE 14.

In FIGURES 4 to 9 are shown a number of suitable arrangements ofcontinuous belt or series of continuous belts mounted for variousapplications. It will often be advantageous to allow the belt to enterthe liquid at an angle. One particular advantage is when a small amountof the liquid to be separated has appeared as a separate film as the topof the liquid in the reservoir, the angled belt has a greater distanceto travel through the separate film and consequently the time of contactbetween belt and the liquid to be absorbed thereon is increased.

FIGURES 7 and 9, besides illustrating the series of belts and acontinuous belt running over a series of loops dipping into the body ofliquid, also illustrates a device in which the lower pulley hangs in theloops (like a Diablo or Yo Yo) continually rolling to its bottom bygravity, without need for fixed bearings or an axle on which to rotate.

FIGURE 8 shows novel apparatus wherein a single belt may be used formultiple removal operations concurrently by passing it over multiplepulleys to give a plurality of loops each of which can act as describedabove.

FIGURES 10 to 13 and show a number of methods useful for removing liquidfrom the belt on the apparatus of the invention.

FIGURE 11 shows a squeeze-roll removal method where rolls 66 are held bysprings 68. These rolls are advantageously placed with their axis at asuflicient angle to the horizontal to allow the oil to run offlaterally.

FIGURE 12 shows vacuum line 70 placed adjacent to the belt and drawingliquid into the lines through openings 72.

FIGURES 13 and 15 show methods of blowing the absorbed liquid from thebelt surface. Air is applied under pressure from blower lines 74. Theliquid receivers 76 are designed and positioned, depending on whetherthe belt is permeable (FIG. 13) or impermeable (as in FIG. 14).

In this application and accompanying drawings, I have shown anddescribed a preferred embodiment of my invention and have suggestedvarious alternatives and modifications thereof, but it is to beunderstood that these are not intended to be exhaustive and that otherchanges and modifications can be made within the scope of the invention.These suggestions herein are selected and included for purposes ofillustration in order that others skilled in the art will more fullyunderstand the invention and the principles thereof and will be enabledto modify it and embody it in a variety of forms, each as may be bestsuited to the condition of a particular case.

I claim:

1. A process of separating a liquid from a mixture of liquids havingsubstantially diliering dielectric properties comprising continuouslypassing a belt having a dielectric constant of substantially the sameorder as the liquid to be separated through a path partially submergedin said mixture, thereby coating said belt with said liquid to beseparated, and continuously removing said liquid from said belt.

2. An apparatus for separating liquids of substantially differingdielectric properties comprising a continuous belt the surface of whichis of substantially the same order of dielectric constant as a firstliquid to be removed from a liquid mixture, said belt forming areceptive surface on which said first liquid preferentially adheres; aplurality of pulleys on which said belt operates; at least one pulleyextending beneath the surface of said liquid mixture, said pulley whichextends beneath the surface having open areas for passage of said liquidmixture into contact with the underside of said belt while on saidpulley, and means for removing from said belt said first liquid whichadheres thereto.

3. An apparatus as in claim 2 wherein said belt surface is of a materialhaving a dielectric constant of about 1 to 5 and wherein said firstliquid to be removed has a dielectric constant less than about 5.

4. An apparatus as in claim 2 wherein said belt surface is of a materialhaving a dielectric constant less than about 2.3.

5. An apparatus as in claim 2 wherein one of said pulley operatesexternally of said liquid mixture comprises an outer periphery definedby a spiral rib, having a periphery speed different from the speed ofsaid belt and adapted for moving liquid across a belt passing over saidperiphery, toward one side of said belt.

6. An apparatus as in claim 5 wherein said spiral rib comprises twosections meeting approximately at the midpoint of the pulley, each saidsection comprising a coil wound oppositely with respect to the coil ofthe remaining section.

7. An apparatus for separating liquids of substantially differingdielectric properties comprising a continuous belt the surface of whichis substantially the same order of dielectric constant as a first liquidto be removed from a liquid mixture said belt forming a receptivesurface on which said first liquid preferentially adheres; at least onepulley on which said belt operates through a path which is partiallythrough said liquid mixture, at least one said pulley extending beneaththe surface having open areas for passage of said liquid mixture intocontact with the underside of said belt while on said pulley, and meansfor removing from said belt said first liquid which adheres thereto.

8. An apparatus as in claim 7 wherein the surface of said belt isirregular forming means to retain oil on said surface.

References Cited UNITED STATES PATENTS 1,826,801 10/1931 Littleford 155O2,959,288 11/1960 FOWler 2l0222 3,017,031 1/ 1962 Fowler 2102223,063,407 11/1962 Bergstein 118118 3,146,192 8/1964 McClintOck 21040JOSEPH SCOVRONEK, Primary Exwminer.

MORRIS O. WOLK, Examiner.

E. G. WHITBY, Assistant Examiner.

1. A PROCESS OF SEPARATING A LIQUID FROM A MIXTURE OF LIQUIDS HAVINGSUBSTANTIALLY DIFFERING DIELECTRIC PROPERTIES COMPRISING CONTINUOUSLYPASSING A BELT HAVING A DIELECTRIC CONSTANT OF SUBSTANTIALLY THE SAMEORDER AS THE LIQUID TO BE SEPARATED THROUGH A PATH PARTIALLY SUBMERGEDIN SAID MIXTURE, THEREBY COATING SAID BELT WITH SAID LIQUID TO BESEPARATED, AND CONTINUOUSLY REMOVING SAID LIQUID FROM SAID BELT.